Low-emission zones (LEZs)
- LEZs restrict the most polluting vehicles from entering certain city areas.
- Common in large city centres; often enforced using number-plate recognition cameras.
- Benefits: improved air quality; fewer respiratory problems; quieter streets; encourages public transport and cycling.
- Drawbacks: can be expensive for drivers and small businesses (upgrading vehicles); concerns about fairness for low-income residents.
- Some cities offer exemptions, grants or phased introduction to reduce negative impact.
Changes after introducing LEZs (selected cities)
| City | Country | Year introduced | Estimated NO₂ reduction in city centre | Urban population |
| London | United Kingdom | 2019 | 36% | 8 million |
| Madrid | Spain | 2018 | 23% | 3.3 million |
| Milan | Italy | 2012 | 18% | 1.4 million |
